From: Oliver Neukum <oliver@neukum.org>
To: Arjan van de Ven <arjan@infradead.org>
Subject: Re: [2.6 patch] i386: always use 4k stacks
Date: Wed, 16 Nov 2005 09:34:21 +0100
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Am Mittwoch, 16. November 2005 09:03 schrieb Arjan van de Ven:
> * less CPU cache footprint due to interrupt stacks
>    - interrupt stacks are per cpu now instead of borrowing the per
>      thread stack space; this both has less impact on the caches, and
>      has more cache hits; the per cpu stack will be in cache more than
>      the previously scattered bits and pieces
> * more stack space is available for interrupts compared to 2.4 kernels
>    - in 2.4 kernels only 2Kb was available for interrupt context (to
>      keep 4K available for user context). With complex softirqs such as
>      PPP and firewall rules and nested interrupts this wasn't always
>      enough. Compared to 2.6-with-8Kstacks is a bit harder; there is
>      2Kb extra available there compared to 2.4 and arguably some of that
>      extra is for interrupts.

This is due to having interrupt stacks. Is there any reason not to have
8K task stacks and per CPU interrupt stacks?

	Regards
		Oliver

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